1. Field of the Invention
The present invention is directed generally to systems and methods for providing progressive downloading of content over a network, and more specifically, to progressive downloading of content using available surplus capacity of a network.
2. Description of the Related Art
Streaming online content while connected to a network is a popular method of delivering requested media content from networked servers for consumption by a requestor. A familiar problem with streaming online content is that the network connecting the server and a receiver may have transient fluctuations in its ability to deliver the content, resulting in interruptions in the playback (or “playout”) session. Various methods have been proposed to mitigate this issue including content compression to reduce the delivery rate, dynamic real-time encoding to reduce the delivery rate/playback-quality to match the network capability, and pre-buffering a short segment of the content before allowing playback to start and thereafter filling the buffer faster than the content can be played out until the end of the playback session. This last streaming method has become known as progressive download (or “PD”), and the technique is intended to build up a safety margin in order to be able to maintain continuous playback during brief intervals when the server is unable to maintain the delivery rate to the receiver over the network.
While designed to reduce and to avoid interruptions, progressive download is not immune to network impairments which persist long enough to empty a buffer on a system receiving the content. In those cases, the playback session is forced to halt until the buffer can again be re-filled and the session recommences. It is therefore a common experience that existing progressive download techniques often fail to provide a continuous playback session depending on the capabilities of the network.
Another growing problem is the impact that streaming large content files has on access networks including wired, fiber and wireless types. “Large” media content has the signature feature of consuming significant amounts of time and network resources during its delivery to or from an end user device. Commonly, consumer access networks are designed for delivery of short bursts of data and network resource use and are not intended for long-term continuous use such as streaming media content. Streaming media content is widely acknowledged to be a principal challenge to access network traffic engineers who try to satisfy the peak use demands of many users with limited network resources. The typical outcome of widespread streaming adoption is network congestion which often is exhibited by slow network response for all users and their applications.